The 66-year-old media personality will spend three weeks on stage at London’s Eventim Apollo for the musical role this December, where she will star alongside Danny Dyer and Rylan Clark-Neal.
Danny - who is known for his role in BBC soap ‘EastEnders’ - starred in the musical last year as The Producer, and is set to return this year.
In an interview with The Sun newspaper’s Bizarre column, Sharon said: “I’m going to be coming to do the Nativity at the Apollo over Christmas.
“This is the way it was. For three years they’ve been asking me, ‘Do it, do it, please do it’. I’m like, ‘yeah I’d love to do it’.
"So I’m going to do it this year and I’m excited about it, working with all those kids, 31 kids. Danny is in it this year, of course.
"It’s going to be amazing. Danny is coming back.”
But although Sharon has a history with the music industry after managing her husband Ozzy Osbourne’s band Black Sabbath, and judging talent on ‘The X Factor’, she’s joked audiences will “walk out” when they hear her sing.
She added: “I sing terribly and it will be very funny. They’ll walk out. You’ll hear these huge amount of boos when I sing.”
As of the time of writing, Sharon’s role in the musical has not yet been revealed, but she will follow in the footsteps of pal Louis Walsh and comedian Jo Brand, who have both featured in the show.
‘Nativity! The Musical’ is based on the 2009 film of the same name, which follows a group of primary school children whose teacher Mr Poppy has ambitions to turn their musical nativity into a Hollywood movie.
The show is hoping to repeat its successes from 2017 and 2018, and will start with a UK tour in October before returning to the capital for Christmas, where it will run from December 11 to 29.